Kernel: Implement unified input files for device hot-plugging support

/dev/keyboard and /dev/mouse can be read for events from any attached
keyboard or mouse respectively. This makes device hot-plugging support
pretty much automatic for TTY, GUI, and whatever takes input.

kernel/include/kernel/Input/InputDevice.h

@@ -7,7 +7,7 @@
 namespace Kernel
 {
 
-	class InputDevice : public CharacterDevice
+	class InputDevice : public CharacterDevice, public BAN::Weakable<InputDevice>
 	{
 	public:
 		enum class Type
@@ -19,6 +19,9 @@ namespace Kernel
 	public:
 		InputDevice(Type type);
 
+		BAN::StringView name() const final override { return m_name; }
+		dev_t rdev() const final override { return m_rdev; }
+
 	protected:
 		void add_event(BAN::ConstByteSpan);
 
@@ -28,8 +31,9 @@ namespace Kernel
 		bool can_write_impl() const override { return false; }
 		bool has_error_impl() const override { return false; }
 
-		virtual BAN::StringView name() const final override { return m_name; }
-		virtual dev_t rdev() const final override { return m_rdev; }
+
+	private:
+		BAN::ErrorOr<size_t> read_non_block(BAN::ByteSpan);
 
 	private:
 		const dev_t m_rdev;
@@ -47,6 +51,63 @@ namespace Kernel
 		size_t m_event_tail { 0 };
 		size_t m_event_head { 0 };
 		size_t m_event_count { 0 };
+
+		friend class KeyboardDevice;
+		friend class MouseDevice;
+	};
+
+
+
+	class KeyboardDevice : public CharacterDevice
+	{
+	public:
+		static BAN::ErrorOr<BAN::RefPtr<KeyboardDevice>> create(mode_t mode, uid_t uid, gid_t gid);
+
+		void notify() { m_semaphore.unblock(); }
+
+	private:
+		KeyboardDevice(mode_t mode, uid_t uid, gid_t gid);
+		BAN::ErrorOr<size_t> read_impl(off_t, BAN::ByteSpan) override;
+
+		bool can_read_impl() const override;
+		bool can_write_impl() const override { return false; }
+		bool has_error_impl() const override { return false; }
+
+		BAN::StringView name() const final override { return m_name; }
+		dev_t rdev() const final override { return m_rdev; }
+
+	private:
+		const dev_t m_rdev;
+		const BAN::StringView m_name;
+		Semaphore m_semaphore;
+
+		friend class BAN::RefPtr<KeyboardDevice>;
+	};
+
+	class MouseDevice : public CharacterDevice
+	{
+	public:
+		static BAN::ErrorOr<BAN::RefPtr<MouseDevice>> create(mode_t mode, uid_t uid, gid_t gid);
+
+		void notify() { m_semaphore.unblock(); }
+
+	private:
+		MouseDevice(mode_t mode, uid_t uid, gid_t gid);
+		BAN::ErrorOr<size_t> read_impl(off_t, BAN::ByteSpan) override;
+
+		bool can_read_impl() const override;
+		bool can_write_impl() const override { return false; }
+		bool has_error_impl() const override { return false; }
+
+		BAN::StringView name() const final override { return m_name; }
+		dev_t rdev() const final override { return m_rdev; }
+
+	private:
+		const dev_t m_rdev;
+		const BAN::StringView m_name;
+		Semaphore m_semaphore;
+
+		friend class BAN::RefPtr<MouseDevice>;
 	};
 
 }

kernel/kernel/FS/DevFS/FileSystem.cpp

@@ -5,6 +5,7 @@
 #include <kernel/Device/ZeroDevice.h>
 #include <kernel/FS/DevFS/FileSystem.h>
 #include <kernel/FS/TmpFS/Inode.h>
+#include <kernel/Input/InputDevice.h>
 #include <kernel/Lock/LockGuard.h>
 #include <kernel/Process.h>
 #include <kernel/Scheduler.h>
@@ -26,6 +27,8 @@ namespace Kernel
 		s_instance->add_device(MUST(DebugDevice::create(0666, 0, 0)));
 		s_instance->add_device(MUST(NullDevice::create(0666, 0, 0)));
 		s_instance->add_device(MUST(ZeroDevice::create(0666, 0, 0)));
+		s_instance->add_device(MUST(KeyboardDevice::create(0440, 0, 901)));
+		s_instance->add_device(MUST(MouseDevice::create(0440, 0, 901)));
 	}
 
 	DevFileSystem& DevFileSystem::get()

kernel/kernel/Input/InputDevice.cpp

@@ -1,4 +1,5 @@
 #include <kernel/Device/DeviceNumbers.h>
+#include <kernel/FS/DevFS/FileSystem.h>
 #include <kernel/Input/InputDevice.h>
 #include <kernel/Lock/LockGuard.h>
 
@@ -10,8 +11,11 @@
 namespace Kernel
 {
 
-	static BAN::Atomic<uint16_t> s_next_keyboard { 0 };
-	static BAN::Atomic<uint16_t> s_next_mouse { 0 };
+	static BAN::Vector<BAN::WeakPtr<InputDevice>> s_keyboards;
+	static BAN::RefPtr<KeyboardDevice> s_keyboard_device;
+
+	static BAN::Vector<BAN::WeakPtr<InputDevice>> s_mice;
+	static BAN::RefPtr<MouseDevice> s_mouse_device;
 
 	static const char* get_name_format(InputDevice::Type type)
 	{
@@ -30,9 +34,15 @@ namespace Kernel
 		switch (type)
 		{
 			case InputDevice::Type::Keyboard:
-				return makedev(DeviceNumber::Keyboard, s_next_keyboard++);
+				for (size_t i = 0; i < s_keyboards.size(); i++)
+					if (!s_keyboards[i].valid())
+						return makedev(DeviceNumber::Keyboard, i + 1);
+				return makedev(DeviceNumber::Keyboard, s_keyboards.size() + 1);
 			case InputDevice::Type::Mouse:
-				return makedev(DeviceNumber::Mouse, s_next_mouse++);
+				for (size_t i = 0; i < s_mice.size(); i++)
+					if (!s_mice[i].valid())
+						return makedev(DeviceNumber::Mouse, i + 1);
+				return makedev(DeviceNumber::Mouse, s_mice.size() + 1);
 		}
 		ASSERT_NOT_REACHED();
 	}
@@ -52,11 +62,25 @@ namespace Kernel
 	InputDevice::InputDevice(Type type)
 		: CharacterDevice(0440, 0, 901)
 		, m_rdev(get_rdev(type))
-		, m_name(MUST(BAN::String::formatted(get_name_format(type), minor(m_rdev))))
+		, m_name(MUST(BAN::String::formatted(get_name_format(type), minor(m_rdev) - 1)))
 		, m_type(type)
 		, m_event_size(get_event_size(type))
 	{
 		MUST(m_event_buffer.resize(m_event_size * m_max_event_count, 0));
+
+		if (m_type == Type::Keyboard)
+		{
+			if (s_keyboards.size() < minor(m_rdev))
+				MUST(s_keyboards.resize(minor(m_rdev)));
+			s_keyboards[minor(m_rdev) - 1] = MUST(get_weak_ptr());
+		}
+
+		if (m_type == Type::Mouse)
+		{
+			if (s_mice.size() < minor(m_rdev))
+				MUST(s_mice.resize(minor(m_rdev)));
+			s_mice[minor(m_rdev) - 1] = MUST(get_weak_ptr());
+		}
 	}
 
 	void InputDevice::add_event(BAN::ConstByteSpan event)
@@ -94,6 +118,10 @@ namespace Kernel
 		m_event_count++;
 
 		m_event_semaphore.unblock();
+		if (m_type == Type::Keyboard && s_keyboard_device)
+			s_keyboard_device->notify();
+		if (m_type == Type::Mouse && s_mouse_device)
+			s_mouse_device->notify();
 	}
 
 	BAN::ErrorOr<size_t> InputDevice::read_impl(off_t, BAN::ByteSpan buffer)
@@ -121,4 +149,113 @@ namespace Kernel
 		return m_event_size;
 	}
 
+	BAN::ErrorOr<size_t> InputDevice::read_non_block(BAN::ByteSpan buffer)
+	{
+		if (buffer.size() < m_event_size)
+			return BAN::Error::from_errno(ENOBUFS);
+
+		SpinLockGuard _(m_event_lock);
+
+		if (m_event_count == 0)
+			return 0;
+
+		memcpy(buffer.data(), &m_event_buffer[m_event_tail * m_event_size], m_event_size);
+		m_event_tail = (m_event_tail + 1) % m_max_event_count;
+		m_event_count--;
+
+		return m_event_size;
+	}
+
+
+
+	BAN::ErrorOr<BAN::RefPtr<KeyboardDevice>> KeyboardDevice::create(mode_t mode, uid_t uid, gid_t gid)
+	{
+		s_keyboard_device = TRY(BAN::RefPtr<KeyboardDevice>::create(mode, uid, gid));
+		return s_keyboard_device;
+	}
+
+	KeyboardDevice::KeyboardDevice(mode_t mode, uid_t uid, gid_t gid)
+		: CharacterDevice(mode, uid, gid)
+		, m_rdev(makedev(DeviceNumber::Keyboard, 0))
+		, m_name("keyboard"_sv)
+	{}
+
+	BAN::ErrorOr<size_t> KeyboardDevice::read_impl(off_t, BAN::ByteSpan buffer)
+	{
+		if (buffer.size() < sizeof(LibInput::RawKeyEvent))
+			return BAN::Error::from_errno(ENOBUFS);
+
+		for (;;)
+		{
+			for (auto& weak_keyboard : s_keyboards)
+			{
+				auto keyboard = weak_keyboard.lock();
+				if (!keyboard)
+					continue;
+
+				auto bytes = TRY(keyboard->read_non_block(buffer));
+				if (bytes > 0)
+					return bytes;
+			}
+
+			LockFreeGuard _(m_mutex);
+			TRY(Thread::current().block_or_eintr_indefinite(m_semaphore));
+		}
+	}
+
+	bool KeyboardDevice::can_read_impl() const
+	{
+		for (auto& weak_keyboard : s_keyboards)
+			if (auto keyboard = weak_keyboard.lock())
+				if (keyboard->can_read())
+					return true;
+		return false;
+	}
+
+
+
+	BAN::ErrorOr<BAN::RefPtr<MouseDevice>> MouseDevice::create(mode_t mode, uid_t uid, gid_t gid)
+	{
+		s_mouse_device = TRY(BAN::RefPtr<MouseDevice>::create(mode, uid, gid));
+		return s_mouse_device;
+	}
+
+	MouseDevice::MouseDevice(mode_t mode, uid_t uid, gid_t gid)
+		: CharacterDevice(mode, uid, gid)
+		, m_rdev(makedev(DeviceNumber::Mouse, 0))
+		, m_name("mouse"_sv)
+	{}
+
+	BAN::ErrorOr<size_t> MouseDevice::read_impl(off_t, BAN::ByteSpan buffer)
+	{
+		if (buffer.size() < sizeof(LibInput::MouseEvent))
+			return BAN::Error::from_errno(ENOBUFS);
+
+		for (;;)
+		{
+			for (auto& weak_mouse : s_mice)
+			{
+				auto mouse = weak_mouse.lock();
+				if (!mouse)
+					continue;
+
+				auto bytes = TRY(mouse->read_non_block(buffer));
+				if (bytes > 0)
+					return bytes;
+			}
+
+			LockFreeGuard _(m_mutex);
+			TRY(Thread::current().block_or_eintr_indefinite(m_semaphore));
+		}
+	}
+
+	bool MouseDevice::can_read_impl() const
+	{
+		for (auto& weak_mouse : s_mice)
+			if (auto mouse = weak_mouse.lock())
+				if (mouse->can_read())
+					return true;
+		return false;
+	}
+
 }

kernel/kernel/Terminal/TTY.cpp

@@ -83,10 +83,10 @@ namespace Kernel
 		Process::create_kernel(
 			[](void*)
 			{
-				auto file_or_error = VirtualFileSystem::get().file_from_absolute_path({ 0, 0, 0, 0 }, "/dev/keyboard0"_sv, O_RDONLY);
+				auto file_or_error = VirtualFileSystem::get().file_from_absolute_path({ 0, 0, 0, 0 }, "/dev/keyboard"_sv, O_RDONLY);
 				if (file_or_error.is_error())
 				{
-					dprintln("no input device found");
+					dprintln("no keyboard found");
 					return;
 				}
 

kernel/kernel/kernel.cpp

@@ -205,9 +205,8 @@ static void init2(void*)
 	// Initialize empty keymap
 	MUST(LibInput::KeyboardLayout::initialize());
 
-	// FIXME: implement device hot plugging, so multiple devices is possible
-	//if (auto res = PS2Controller::initialize(); res.is_error())
-	//	dprintln("{}", res.error());
+	if (auto res = PS2Controller::initialize(); res.is_error())
+		dprintln("{}", res.error());
 
 	MUST(NetworkManager::initialize());
 
@@ -216,9 +215,6 @@ static void init2(void*)
 	PCI::PCIManager::get().initialize_devices();
 	dprintln("PCI devices initialized");
 
-	// FIXME: This is very hacky way to wait until USB stack is initialized
-	SystemTimer::get().sleep(500);
-
 	VirtualFileSystem::initialize(cmdline.root);
 	dprintln("VFS initialized");
 

userspace/programs/WindowServer/main.cpp

@@ -158,11 +158,11 @@ int main()
 	MUST(LibInput::KeyboardLayout::initialize());
 	MUST(LibInput::KeyboardLayout::get().load_from_file("/usr/share/keymaps/us.keymap"_sv));
 
-	int keyboard_fd = open("/dev/keyboard0", O_RDONLY);
+	int keyboard_fd = open("/dev/keyboard", O_RDONLY);
 	if (keyboard_fd == -1)
 		perror("open");
 
-	int mouse_fd = open("/dev/mouse0", O_RDONLY);
+	int mouse_fd = open("/dev/mouse", O_RDONLY);
 	if (mouse_fd == -1)
 		perror("open");
 

userspace/tests/test-mouse/main.cpp

@@ -50,7 +50,7 @@ void cleanup()
 int main(int argc, char** argv)
 {
 	const char* fb_path = "/dev/fb0";
-	const char* mouse_path = "/dev/mouse0";
+	const char* mouse_path = "/dev/mouse";
 
 	if (argc == 1)
 		;